Ensure that TableMigration Test Covers DB Names
Ensure that TableMigration Test Covers DB Names

Test cases as written didn't cover the possibility that
`:database_attribute_name` could be set on a key attribute, which if
improperly implemented would result in a hard to track down bug.

Currently, this is implemented correctly and this test passes. As such
there is no associated code change.

awslabs/aws-sdk-ruby-record